Forecast Review - Feb 3, 2018

Feb 4 2018 1:30 PM CST| 0 Comments | Wisconsin | Storm Events

Forecast reviews are written mostly for myself to help improve future forecasts. I care deeply about the success and accuracy of my forecasts. I share my observations with you so we can learn together but also to demonstrate this process is more than just regurgitating a model forecast or taking somebody else's idea.

SUMMARY

In the last 12-24hrs forecast models trended wetter, snowier for central & southern Wisconsin. The 00/12Z model run as the event began showed and increase to 0.5" of QPF in east central Wisconsin. All models showed higher QPF amounts in central or southern Wisconsin before the event. Much of that was within a region of strong WAA forcing as the low swung by to the south, and then on the deformation band on Sunday morning as the system consolidated and moved away.

The main snow band was further south than I expected, positioned west-east across Fond du Lac. Kind of surprised actually. Most of the QPF was over southern Wisconsin like the Canadian model which I considered to be an outlier.

Successes

  • New forecasting technique to calculate snow accumulations by region was successful. Had I followed Kuchera I would have had 11.0" of snow in east-central Wisconsin.

  • Keypoint of 4-6" with lesser amounts west. A few spots went over and that's acceptable.

  • 4-5" in northeast Wisconsin. The 6" amounts were the combination of Friday night activity and a mesoscale feature. I wanted to de-emphasize this region. I missed in upper Michigan though.

  • Knowing which models to believe and when. New forecast strategy helped with this.

Failures

  • Early forecasts were not good. I said ahead of time that things were not going to go smoothly. There are things I can do to help like not post snow maps too early. The Friday map was not intended to be the focal point of the update, mistake on my part. The Thurs-Fri forecasts would probably get a D grade. Nobody did well here and I'm not sure how you could have with the way things were and how they ended up. I had a problem finding good information to share in the 36-72HR timeframe, felt like I was in a vaccum.

  • Didn't follow through on thoughts. I opted to play it safe and line up closer to the advisories. I can't tell you the number of times this season I've made the mistake of letting outside ideology pollute my own ideology. In the past if I didn't have awareness of what others were doing then I would miss something. I am really close to cutting connection to outside sources and going completely rogue. Sink or swim time.

  • I applied snow ratios in correctly, going with 22:1 north and 14:1 south on the final forecast. There was east to west variation. Far southern Wisconsin was closer to 10-12:1. They changed during the event. Broad brushing from start to finish opens the door for issues.

  • Communication on timing and general progression Thurs-Fri was not good. I tried to separate the forcing mechanisms, and I was right about forcing but wrong about timing. In real time it blended to together. I feel good about this but know I can be clearer. The correction is less detail early in the forecast. Nobody likes to hear it but this is the only way to improve accuracy.

  • I would have never gone to 8" in Milwaukee, *maybe* with lake enhancement. Small things making big differences, such as snow ratios early in the event and heavy snow Sunday morning.

Forecast Grade

I'm giving this one a C, lower than the last event. I feel better than the last event. I was right about the southern trend and generally correct about the totals across Wisconsin by the final forecast. I feel good about the end result but bad about the the early forecasts, they were not good. This event was a test of a new forecasting strategy which helped at the end, but not right away.

On the final forecast which came out as the event was already in progress; there is a difference between forecasting and thinking. In this case my thinking at the end should have been followed through. This is hard to do when the rest of the world does not support your view. Also, knee jerk reactions to short term trends is not always a good strategy. Will have to find the balance between the multiple ideologies I've got going right now.

I think this event gives me confidence moving forward to be more confident late in the forecast.


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